NISAR (satellite)

The NASA-ISRO Synthetic Aperture Radar, or NISAR satellite, will use advanced radar imaging to map the elevation of Earth's land and ice masses four to six times a month at resolutions of 5 to 10 meters.{{cite web|url=https://nisar.jpl.nasa.gov/files/nisar/NISAR_Applications_Landslides.pdf|title=Landslide Hazards to Infrastructure|date=2017|website=nisar.jpl.nasa.gov|archive-url=https://web.archive.org/web/20190321133739/https://nisar.jpl.nasa.gov/files/nisar/NISAR_Applications_Landslides.pdf|archive-date=21 March 2019|publisher=NASA (JPL)|access-date=16 March 2021}} {{PD-notice}} It is designed to observe and measure some of the planet's most complex natural processes, including ecosystem disturbances, ice-sheet collapse, and natural hazards such as earthquakes, tsunamis, volcanoes and landslides.{{cite web|url=http://nisar.jpl.nasa.gov/|title=NASA-ISRO SAR Mission (NISAR)|publisher=Jet Propulsion Laboratory|access-date=16 March 2021}} {{PD-notice}}{{cite web|url=https://nisar.jpl.nasa.gov/system/documents/files/26_NISAR_FINAL_9-6-19.pdf|title=NASA-ISRO SAR (NISAR) Mission Science Users' Handbook|publisher=NASA|access-date=27 May 2021}} {{PD-notice}}

The mission is a partnership between NASA and ISRO. Under the terms of the agreement, NASA will provide the mission's L-band synthetic aperture radar (SAR), a high-rate telecommunication subsystem for scientific data GPS receivers, a solid-state recorder, and a payload data subsystem. ISRO will provide the satellite bus, an S-band synthetic aperture radar (SAR), the launch vehicle, and associated launch services.{{cite web|url=http://www.nasa.gov/press/2014/september/us-india-to-collaborate-on-mars-exploration-earth-observing-mission/|title=U.S., India to Collaborate on Mars Exploration, Earth-Observing Mission|publisher=NASA|date=30 September 2014|access-date=16 March 2021}} {{PD-notice}}

All data from NISAR will be freely available one to two days after observation and within hours in case of emergencies like natural disasters. Data collected from NISAR will reveal information about the evolution and state of Earth's crust, help scientists better understand our planet's natural processes and changing climate, and aid future resource and hazard management.

The satellite will be three-axis stabilized. It will use a {{cvt|12|m}} deployable mesh antenna and will operate on both the L- and S- microwave bands. The aperture mesh reflector (antenna) will be supplied by Astro Aerospace.{{cite press release|url=http://globenewswire.com/news-release/2015/10/30/781817/10154634/en/NASA-Jet-Propulsion-Laboratory-Selects-Northrop-Grumman-s-Astro-Aerospace-for-NISAR-Reflector.html|title=NASA Jet Propulsion Laboratory Selects Northrop Grumman's Astro Aerospace for NISAR Reflector|last=White|first=AnnaMaria|publisher=Northrop Grumman Corporation|agency=GlobeNewswire|date=30 October 2015|access-date=16 March 2021}}

The National Centre of Geodesy facilities at IIT-Kanpur and IIT-Patna will host a corner reflector for NISAR.It will play a key role in calibration and course correction of the Nisar satellite's radar during the in-orbit checkout phase.

ISRO's share of the project cost is about {{INRConvert|788|c}}, and NASA's share is about US$1,118 million.{{cite web|url=http://164.100.158.235/question/annex/243/Au2223.pdf|title=Rajya Sabha Q. No.2223, Session:243 "JOINT PROJECT BETWEEN NASA AND ISRO"|date=3 August 2017|publisher=Department of Space|archive-url=https://web.archive.org/web/20170803212014/http://164.100.158.235/question/annex/243/Au2223.pdf|archive-date=3 August 2017|url-status=dead|access-date=16 March 2021}}{{cite news|url=http://pib.nic.in/newsite/PrintRelease.aspx?relid=169570|title=Joint Project between NASA and ISRO|date=3 August 2017|publisher=Press Information Bureau, Government of India|access-date=16 March 2021}}{{Cite web |date=June 2024 |title=United States Government Accountability Office Report to Congressional Committees: NASA Assessments of Major Projects GAO-24-106767 |url=https://www.gao.gov/assets/gao-24-106767.pdf |page=81}}

The satellite was originally scheduled to be launched from India aboard a GSLV Mark II on 30 March 2024, but it was postponed until further notice due to a needed hardware update.{{cite web |last=Foust |first=Jeff |url=https://spacenews.com/antenna-work-delays-nisar-launch/ |title=Antenna work delays NISAR launch |work=SpaceNews |date=24 March 2024 |access-date=2 April 2024}} The orbit will be a sun-synchronous, dawn-to-dusk type. The planned mission life is three years. The satellite was fully integrated in January 2024 and was performing its final testing and analysis in preparation for launch. However, in an interview with the Times of India, Chairman of ISRO Sreedhara Panicker Somanath said that though the GSLV for NISAR will be built by March-April, the satellite is still undergoing tests and they were expecting some delay.{{Cite news |date=2024-03-19 |title=Nisar only in 2nd half of 2024; Trishna gets nod |url=https://timesofindia.indiatimes.com/india/nisar-only-in-2nd-half-of-2024-trishna-gets-nod/articleshow/108620945.cms |access-date=2024-03-23 |work=The Times of India |issn=0971-8257}} Tests found that the reflector might face higher-than-expected temperatures when stowed during flight and so it was returned to the manufacturer in California to apply a reflective coating to mitigate the risk of overheating.{{Cite web |title=Isro's Nisar mission launch delayed, key component sent back to NASA |url=https://www.indiatoday.in/science/story/isros-nisar-mission-launch-delayed-key-component-sent-back-to-nasa-2518594-2024-03-23 |access-date=2024-03-23 |website=India Today |date=23 March 2024 |language=en}}{{Cite web |date=2024-03-22 |title=Work Continues on NISAR Satellite as Mission Looks Toward Launch – NASA-ISRO SAR Mission (NISAR) |url=https://blogs.nasa.gov/nisar/2024/03/22/work-continues-on-nisar-satellite-as-mission-looks-toward-launch/ |access-date=2024-03-23 |website=blogs.nasa.gov |language=en-US}}

On 15 October 2024, after the completion of all checks and tests, NASA's C-130 took off from Wallops Flight Facility in Virginia to embark on the multi-leg, multi-day journey to India. The flight will first stop at March Air Reserve Base to retrieve the spacecraft followed by strategic stops at Hickam Air Force Base, Hawaii; Andersen Air Force Base, Guam; Clark Air Base, Philippines and reach HAL Airport in Bengaluru, India.{{Cite web |title=NASA's C-130 Aircraft En Route to India in Support of NISAR Mission - NASA |url=https://www.nasa.gov/image-article/nasas-c-130-aircraft-en-route-to-india-in-support-of-nisar-mission/ |access-date=2024-10-19 |language=en-US}}{{Cite web |last1=Pillai |first1=Soumya |last2=ThePrint |date=2024-10-18 |title=US C-130 en route to India with critical payload: NISAR's radar antenna reflector |url=https://theprint.in/science/us-c-130-en-route-to-india-with-critical-payload-nisars-radar-antenna-reflector/2318039/?amp |access-date=2024-10-19 |website=ThePrint |language=en-US}} By late January 2025, the satellite had finished all preliminary checkout in Bengaluru and was shipped to SDSC.{{Cite web |title=NISAR mission launch in next few months: ISRO chief |url=https://www.deccanherald.com/india/nisar-mission-launch-in-next-few-months-isro-chief-3378659#google_vignette |access-date=2025-01-30 |website=Deccan Herald |language=en}}

As of December 2024, NISAR is expected to be launched in 2025.

NISAR diagram.jpg|NISAR diagram

File:NASA-ISRO NISAR satellite inside anechoic chamber at URSC, ISRO.webp|NISAR undergoing tests

File:NASA-ISRO NISAR satellite going through solar array extension testing at ISRO facility.webp|NISAR solar array

File:NASA-ISRO NISAR satellite's DGA antenna.webp|NISAR's DGA antenna

• L-band (1.25 GHz; 24 cm wavelength) polarimetric SAR, to be produced by NASA.
• S-band (3.20 GHz; 9.3 cm wavelength) polarimetric SAR, to be produced by ISRO.{{cite web|url=https://timesofindia.indiatimes.com/Home/Science/Isros-instrument-design-passes-Nasa-review/articleshow/39369930.cms|title=ISRO's instrument design passes Nasa review|newspaper=The Times of India|date=31 July 2014|access-date=16 March 2021}}

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